How Mineral Fiber Insulation Works

Insulation Basics

Insulation works by resisting the flow of heat.

Heat is a form of energy and always seeks a cooler area—in your home, this means it flows outward in winter, and inward in summer. Insulation slows this heat flow, so your heating and cooling system (or systems) requires less operation to maintain your desired temperature, which saves you money. Note that a good air barrier should always accompany mineral fibre insulation on one side, and a good vapour barrier on the other, so that any moisture can dry out.

What Does R-value Mean?

Insulation’s ability to resist heat flow is identified and labelled by R-value, “R”, the imperial unit, or RSI-value, the metric unit. The higher the R-value or RSI-value, the greater the insulating power.

Manufacturers of insulation products print the R-values of their products either on bags or on labels attached to plain bags. In most cases, R-values are also printed on the facings of batts and rolls. On unfaced insulation, the R-value is printed on the product. R-value levels the playing field for insulation, allowing consumers to easily make comparisons between products by knowing that R-value is R-value, regardless of insulation type, location, or any other variable.